ENG | Uploading project to GitHub

Motivation

If you’re a developer working on a project and need to store your code on a remote repository, GitHub is a popular choice. In this post, we’ll walk through the process of initializing a Git repository, adding files, committing changes, and pushing your project to GitHub using the command line interface.

Steps

• Create a new repository on Github (Repositories -> New) and select better name than test-repo
  • Possibly add README.md and license.
• Initialize repository

   $ git init
   Initialized empty Git repository in /home/pavel/projects/2023-05-15-test/.git/
  

• Check status

  $ git status
  On branch main
  
  No commits yet
  
  Untracked files:
    (use "git add <file>..." to include in what will be committed)
      test/
      junk/
  
  nothing added to commit but untracked files present (use "git add" to track)
  

• Add files (well, directory inside may and may not be a good idea)

  $ git add test*
  $ git status
  On branch main
  
  No commits yet
  
  Changes to be committed:
    (use "git rm --cached <file>..." to unstage)
        new file:   test/.gitignore
        new file:   test/CMakeLists.txt
        new file:   test/README.md
        new file:   test/main.cpp
  Untracked files:
    (use "git add <file>..." to include in what will be committed)
        junk/
  

• Commit changes

  $ git commit -m "initial commit"
  [main (root-commit) 369bcaf] initial commit
   4 files changed, 502 insertions(+)
   create mode 100644 test/.gitignore
   create mode 100644 test/CMakeLists.txt
   create mode 100644 test/README.md
   create mode 100644 test/main.cpp
  

• Verify

  $ git log
  commit 369bcaf7efc01b3640e09a713a8189db267e8fae (HEAD -> main)
  Author: Pavel Perina <[email protected]>
  Date:   Mon May 15 22:09:23 2023 +0100
  
    initial commit
  

  $ git status
  On branch main
  Untracked files:
    (use "git add <file>..." to include in what will be committed)
        junk/
    
  nothing added to commit but untracked files present (use "git add" to track)
  

• Add remote repository

  $ git remote add origin [email protected]:pavel-perina/test-repo
  

• Push to github

  $git push -u -f origin main
  The authenticity of host 'github.com (140.82.121.3)' can't be established.
  ED25519 key fingerprint is SHA256:+DiY3wvvV6TuJJhbpZisF/zLDA0zPMSvHdkr4UvCOqU.
  This key is not known by any other names.
  Are you sure you want to continue connecting (yes/no/[fingerprint])? yes
  Warning: Permanently added 'github.com' (ED25519) to the list of known hosts.
  [email protected]: Permission denied (publickey).
  fatal: Could not read from remote repository.
  
  Please make sure you have the correct access rights
  and the repository exists.
  

  Ok. Maybe I don’t have a SSH key on github. Let’s solve it:

  There is an article about generating SSH keys which has also a paragraph dedicated to GitHub access troubleshooting.

  • Go to github
  • Click on profile icon
  • Go to Settings (close to bottom)
  • Go to SSH and GPG keys
  • Click on New SSH key link
  • Fill in some title (My Linux pub key)
  • Go to ~/.ssh on Linux box
  • Find something suitable, such as id_ecdsa.pub
  • Copy content to clipboard and paste content to github page

    $ cd ~/.ssh
    $ ls
    ...
    $ cat id_ecdsa.pub
    ecdsa-sha2-nistp256 AAAAE....efPg= pavel@... 
    

• Try again

  $ cd ~/projects/2023-05-15-test/
  $ git push
  fatal: The current branch main has no upstream branch.
  To push the current branch and set the remote as upstream, use
  
    git push --set-upstream origin main
  
  To have this happen automatically for branches without a tracking
  upstream, see 'push.autoSetupRemote' in 'git help config'.
  
  $ git push -u -f origin main
  Enumerating objects: 9, done.
  Counting objects: 100% (9/9), done.
  Delta compression using up to 4 threads
  Compressing objects: 100% (7/7), done.
  Writing objects: 100% (9/9), 4.66 KiB | 1.16 MiB/s, done.
  Total 9 (delta 0), reused 0 (delta 0), pack-reused 0 (from 0)
  To github.com:pavel-perina/test-repo
   + 4cde543...369bcaf main -> main (forced update)
  branch 'main' set up to track 'origin/main'.
  

Troubleshooting

Debug connection

GIT_TRACE=1 GIT_SSH_COMMAND="ssh -v" git push

Can’t authenticate during push: remote repository set HTTPS

If you pull your repository using HTTPS and you want to push changes, you may need to change origin from HTTPS to SSH:

[pavel@marten -=- ~/dev-c/slime_mold]$ git remote -v
origin  https://github.com/pavel-perina/slime_mold.git (fetch)
origin  https://github.com/pavel-perina/slime_mold.git (push)
[pavel@marten -=- ~/dev-c/slime_mold]$ git remote set-url origin [email protected]:pavel-perina/slime_mold.git
[pavel@marten -=- ~/dev-c/slime_mold]$ git push
Enumerating objects: 7, done.
Counting objects: 100% (7/7), done.
Delta compression using up to 4 threads
Compressing objects: 100% (4/4), done.
Writing objects: 100% (4/4), 767 bytes | 767.00 KiB/s, done.
Total 4 (delta 3), reused 0 (delta 0), pack-reused 0 (from 0)
remote: Resolving deltas: 100% (3/3), completed with 3 local objects.
To github.com:pavel-perina/slime_mold.git
   21b4d31..d099423  main -> main

Confirm that SSH works

[pavel@marten -=- ~/dev-c/slime_mold]$ ssh -T [email protected]
Hi pavel-perina! You've successfully authenticated, but GitHub does not provide shell access.

Summary

That’s all. It was meant to be brief.